Metal deactivator antioxidants

Although the type and amount of each additive permitted in aviation fuels are strictly limited to color dye, antioxidant, metal deactivator, corrosion inhibitor, fuel system icing inhibitor, static dissipator, and lubricity additive, test methods for checking the concentration present are not specified in every case. In some cases tests to determine the additive content (or its effect) are called for, but in other cases a written statement of its original addition (e.g., at the refinery) is accepted as adequate evidence of its presence. 

After the required amounts of antioxidant, metal deactivator, or corrosion inhibitor have been added to aviation fuels it is not normal to carry out any checks on the concentrations, and no test methods are included in specifications for this purpose. Occasionally a need arises to determine the amount of corrosion inhibitor remaining in a fuel, and several analytical methods have been developed, none of which has yet been standardized. 

J. L. Reyes-Gavilan and R Odorisio, A Review of the Mechanism of Antioxidants, Metal Deactivators and Corrosion-Inhibitors, NLGI Spokesman, 64(II) 22—33 (2001). 

Naugard . [Uniroyal Uniroyal Chem. Ltd.] Antioxidant, metal deactivate, processing aid, polymerization inhibitor, stabilizer for adhesives, diamo-plastic and thermosetpolymors styrene inhibitors. 

Blends of PPE with SBS, and an antioxidant/ metal deactivator (di-octylamine) were developed [Richards and Kelly, 1992 1994 Richards and Pickett, 1995]. Subjected to recycling at temperatures T = 250-350°C (or to thermal aging at T = 50-200°C), the blends maintained excellent retention of impact strength. Similarly, recyclable blends were prepared in two steps (1) PPE was capped with salicyhc acid ester, then blended with... 

Besides antioxidants, metal deactivators, li t stabilizers, fillers, flan retardants, blowing agents, and pigments may be added to a crosslinked system. The right choice is conditioned by the inert behaviour of an additive towards the main reactants of the crosslinking process. 

The presence of the above-mentioned metal ions increases the decomposition rate of hydroperoxides and the overall oxidation rate in the autoxidation of a hydrocarbon to such an extent that even in the presence of antioxidants, the induction period of oxygen uptake is drastically shortened. In such a case, sterically hindered phenols or aromatic amines even at rather high concentrations, do not retard the oxidation rate satisfactorily. A much more efficient inhibition is then achieved hy using metal deactivators, together with antioxidants. Metal deactivators are also known as copper inhihitors, because, in practice, the copper-catalyzed oxidation of polyolefins is by far of greatest importance. This is due to the fact that polyolefins are the preferred insulation material for communication wire and power cables, which generally contain copper conductors. 

For stabilization of polyolefins in contact with copper, it is often mandatory to combine a metal deactivator with an antioxidant. Metal deactivators in actual use are essentially N,N -bis-[3-(3, 5 -di-te t-butyl-4 -hydroxy-phenyl)propionyl]-hydrazine and NJV -dibenzaloxalyldihydrazide. The latter compound requires predispersion in a masterbatch because of its insolubility in polyolefins. This is not needed, however, for the former compound, which at commonly used concentrations is molecularly dispersed in polyolefins after processing. The required additive concentrations range from 0.05 to 0.5% depending on the polymer, the nature of the insulation (solid, cellular), whether the cable is petrolatum filled, and on service conditions. 

Uses Antioxidant, metal deactivator for polymers, PP, HDPE, LDPE, some thermoplastic elastomers used as primary insulation in wire/cable applies., EPDM, peroxide- and radiation-crosslinked PE, nylon, polyacetal, polybutene, PU, styrenic copolymers, unsat. rubber, PVC, PVB, hot-melt and sol n. adhesives, powd. coatings, metal coatings, rubber/plas-tic gaskets, plastic fabricated parts in contact with catalytic metals, oils/ lubricants in contact with metals, food pkg. 

Properties Wh. powd. m.w. 696.92 sp.gr. 1.12 (20 C) m.p. 170-180 C flash pt. (TOC) 260 C Uses Antioxidant, metal deactivator for plastics, polyolefins, PS, polyamides, polyesters, EVA antioxidant/stabilizer for food-grade polymers in food-pkg. adhesives Regulatory FDA 21CFR 175.105, 178.2010 Manuf./Distrib. Crom pton/U ni royal... 

The presence of metal ions can act to increase the oxidation rate, even in the presence of antioxidants. Metal deactivators are often added to prevent this from taking place. Chelating agents are added to complex with the metal ion. 

Vamac requires the use of stabilizers for long service life. The types of stabilizers used in Vamac include antioxidants, metal deactivators, and zinc deactivators. The most effective antioxidants for Vamac are diphenylamines. Table 6.8 contains the recommended stabilizers and suggested levels for various requirements. 

There are thousands of chemical species used as additives, namely antioxidants, metal deactivators, flame retardants, colorants, plasticizers, impact modifiers, lubricants, fungicides, bio-stabilizers, nucleating agents, antistatic agents, crosslinkers, etc. In addition, there are contaminants left after polymerization, compounding or foaming processes. Ideally, the additives should be miscible with the polymer they are supposed to reinforce, protect or color. However, thermodynamics requires that the low molecular... 

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